This invention relates generally to a strap cutting tool of the type used to cut tensioned strapping. In some respects, this invention is an improvement upon the strap cutting tool disclosed in the Applicant's prior Pat. No. 4,644,646 issued Feb. 24, 1987. In other respects, principles of the invention may be applied to similar types of tools that have a working mechanism operated by a pair of handles which are squeezed together.
Problems related to the cutting of tensioned strapping are described in the aforementioned patent. The strap cutting tool disclosed in that patent comprises energy absorbing structures at lateral sides of the cutting mechanism which absorb energy released from the tensioned strapping upon severing. The energy absorbing elements prevent uncontrolled whipping of the severed ends of the strapping from the tool by means of their strategic configuration and arrangement on the tool. The disclosed energy absorbing structures are elastomeric bodies disposed on laterally opposite sides of the cutting mechanism and mounted on the cutting blade by a laterally extending support member attached to the top of the blade. An anvil portion of the tool underlies the energy absorbing structures and contains a centrally disposed slot having an edge with which the cutting edge of the blade coacts to sever strapping when the strapping is disposed between the anvil and the blade, and the tool handles are squeezed together. The energy absorbing structures forcefully hold the strapping against the anvil, compressing in the process, while retaining columnar stability in the direction of force application to the strapping. Upon severing, the energy that has been stored in the tensioned strapping is absorbed into the energy absorbing structures by their laterally yielding while they continue to forcefully hold the severed ends of the strapping against the anvil. In this way, the uncontrolled release of energy in the strapping upon severing is avoided.
One aspect of the present invention relates to improvements in the energy absorbing structures for a strap cutting tool of the type that is disclosed in the aforementioned patent.
While use of elastomeric elements as described in that patent still continue to be preferred, it has been found possible to fabricate energy absorbing structures of suitable resilient metals, such as spring steel, that are formed into particular configurations. Several configurations are specifically disclosed for purposes of explaining principles of this aspect of the present invention.
Other principles of this invention relate to improvements in the fabrication of the tool, and these principles are applicable to various forms of pliers-type tools in addition to the disclosed strap cutting tool.
The tool of Pat. No. 4,644,646 comprises a pair of members pivotally connected together about a pivot. Each member comprises a handle portion and a jaw portion. One member has a lower jaw portion and an associated upper handle portion; the other, an upper jaw portion and an associated lower handle portion. As the handle portions are squeezed together, the resultant action about the pivot results in the jaw portions being closed together to perform the cutting operation. Such a construction contemplates the two members being fabricated as metal forgings. Forging is a process that produces a strong part, but for mass production purposes, it may be too slow to be economical because forgings require subsequent costly machining operations.
Accordingly, the present invention also relates to a novel and unique construction which is particularly well-suited for economical mass production fabrication of a heavy duty industrial pliers-type tool, such as embodied in the disclosed strap cutter. Moreover, these principles allow for the fabrication of a tool which is: esthetically pleasing in design; ergonomic; and functional. Novel features reside in the construction of the handles, the anvil and the blade and in the manner of assembly of the several parts.
The foregoing, along with additional features, advantages and benefits of the invention, will be seen in the ensuing description and claims which are accompanied by drawings. The drawings disclose a preferred embodiment of the invention according to the best mode contemplated at the present time in carrying out the invention.